Targeted phototherapy(TPT) / Excimer laser
Targeted phototherapy (TPT)/ Excimer laser
Phototherapy is a form of skin treatment that involves the delivery of light or ultraviolet radiation. However, targeted phototherapy is an advanced form of phototherapy. In fact, it delivers light or UV radiation directly focused on or targeted at the skin lesion through special delivery mechanisms.
Targeted phototherapy can treat skin disorders like:
- Scalp psoriasis
- Atopic dermatitis
- Seborrheic dermatitis
- Urticaria pigmentosa
- Pityriasis lichenoides
- Mycosis fungoides
- Other skin conditions
How does the procedure work?
Dermatologists perform targeted phototherapy through laser (like Excimer laser) and non-laser devices. Moreover, these devices emit mostly UVB radiation (rarely UVA radiation) in a narrowband wavelength.
It works through the following mechanisms:
- Apoptosis (death) of the relevant pathologic cells: for example, T-cell apoptosis in psoriasis, mycosis fungoides; mast-cell apoptosis in pruritic disorders.
- Stimulation of melanocyte-stimulating hormone. Therefore, this increases pigmentation in vitiligo.
- Decreased release of histamine from both basophils and mast cells: decreases itching in histamine-related disorders like urticaria pigmentosa.
- Alteration in production of inflammatory cell mediators and local immunosuppression. Hence, this helps in treating many skin diseases.
Conventional phototherapy vs Targeted Phototherapy
Advantages of targeted phototherapy
- Exposure of involved skin only: Spares acute side effects like erythema and long-term risk of skin cancer in unaffected skin
- Quick delivery of high doses of energy
- More convenient: shorter and less frequent sessions
- Difficult areas such as scalp, nose, genitals, oral mucosa and ears can be accessed and treated
- Less space-occupying and intimidating
Disadvantages of targeted phototherapy
- More expensive than conventional phototherapy
- One cannot undergo it if more than 10% of body surface area is involved
- Not adequate to treat extensive areas of skin in terms of cost and time involved
Exposure to ultraviolet radiation can lead to acute phototoxicity (like sunburn), and increase the risk of skin ageing and skin cancer. However, the risks of these side effects are low with targeted phototherapy when limited skin is exposed to UV radiation.